Spring biased chair seat



Sept# 11T, 19152' J. P1.: c; vfANf LEEUWEN I 3,053,496'v SPRING BISEIDS @HAIR SEAT 3,053,496 SPRING BIASED CHAIR SEAT Johannes P. C. van Leeuwen, Almelo, Netherlands, as-

signor to Textiel Machines Reading NV., Almelo, Netherlands, a limited-liability company of the Netherlands Filed .'luly 25, 1960, Ser. No. 45,221 3 Claims. (Cl. 248-382) The invention relates to a piece of furniture for use in factories, laboratories, and other places, where work has to be done which, while normally preformed standing at machines, tables and the like and unsuitable for one reason or another for being performed sitting can, with advantage be performed in a half-seated position.

When in the standing position, the body is supported by two points of support, namely the feet, whereas in the half-seated position the weight of the body is supported at three points, viz. both feet and the buttocks, the major part of the weight is borne by the seat of the piece of furniture on which the body rests and only a minor part of the weight is transferred to the floor by the feet.

The invention is concerned with the provision of a chair, stool or similar article (hereinafter referred to generically as a chair) which can be used -in the halfstanding position while giving the user full liberty of movement and without putting the user in a state of unbalance when moving from `one position to the other. Furthermore, the `chair affords security for the user by its stability.

Existing chairs of this general kind which provide for movement of the user in all directions do not provide this stability or the feeling of stable balance, because the user when assuming the half-seated position, has to be careful not to displace the chair too far from the vertical position, as this could lead to overturning of the chair.

The chair in accordance with the invention is designed so as to enable the user, when in the half-seated position, to move sideways and forwardly with the feeling that he will always retain a completely stable position within wide limits.

This is achieved by supporting the seat on a column which is connected to a foot by means of a ball and socket or universal joint, but the movement of which relatively to the foot is limited by a ring which ensures that a vertical line passing through the central point of the seat always falls within the limits of the foot.

Preferably, the ring is shaped so that the user in the half-seated position can move himself forwardly, to the left and to the right but not backwardly. To achieve this purpuose, the ring can have the shape of a sector of a circle.

The foot preferably has four toes disposed similarly to the toes of a fowl, i.e. one toe extending backwardly, one forwardly and the remaining two at angles of about 60 to the forwardly extending toe.

A spring can usefully be provided which biasses the seat column towards its vertical position.

An example of a chair in accordance with the invention is shown in the accompanying drawings, in which- FIGURE 1 shows the chair in sectional elevation; and

3,053,496 Patented Sept. 1l, 1962 FIGURE 2 is a sectional plan taken on the line II-II in FIGURE 1.

The chair shown in the drawings has a foot having four toes 1-2-3--4 The toe 4 extends backwards; the toe 2 extends forwards in line with the toe 4; and the toes 1 and 3 extend forwards and sideways at an angle of about 60 to the toe 2. Between these toes, there is a two-part leg 5, the lower part 6 being connected to the upper part 8 by a universal or ball and socket joint 7 so that the seat 9' xed to the upper part can be displaced `within limits over the surface of a sphere centered at the joint 7.

To limit the movement of the seat, a ring y10 is provided which surrounds the column 5 and is shaped and disposed so that the upper part of the column can be moved out of its vertical position forwardly and sideways but not backwards. As clearly seen in FIGURE 2, the ring has the shape of a sector of a circle and the upper part 8 of the column, when in its vertical position, lies in the crutch of the sector. Thus, the upper part of the column cannot be moved backwards but has freedom of movement forwardly and sideways. A spring 11 is provided which urges the upper part of the column into line with the lower part so that the column always tends to assume a vertical position. The shape and the size of the ring 10 are such that a vertical line from the middle of the seat 9 always falls within the area described by the extremities of the toes 1-2-3-4, so that the chair always remains completely stable and gives a feeling of security to the user.

What is claimed is:

1. A chair comprising a base including a first pair of diametrically opposed toes and a second pair of toes defining therebetween an angle of less than the second pair of toes being symmetrically positioned relative to the first pair, seating means supported on said base for pivotal movement and a rigid ring rigidly supported on `said base and having a peripheral extent, said ring being operatively associated with said seating means to restrict the pivotal movement thereof in conformity with the peripheral extent of the ring, said ring including an arcuate portion having ends and a V-shaped portion `connected to said ends.

2. A chair as claimed in claim 1, wherein said V- shaped portion includes `a pair of legs, said legs being parallel to said second pair of toes.

3. A chair as claimed in claim l, wherein said seating means includes a shaft supported for pivotal movement on said base and a seat on said shaft, said ring surrounding said shaft, the chair `further comprising spring means coupled to said shaft and to said base for elastically resisting pivotal movement of said shaft relative to the base.

References Cited in the file of this patent UNITED STATES PATENTS 239,970 Medart Apr. 12, 1881 612,580 Barnes Oct. 18, 1898 659,089 McKinney Oct. 2, 1900 1,070,278 McKinney Aug. 12, 1913 1,194,551 Schosser Aug. 15, 1916 1,711,526 Forsyth May 7, 1929 FOREIGN PATENTS 700,645 Great Britain Dec. 9. 1953 

